Plate glass is produced by continuously supplying to an apparatus a glass melt, allowing the glass melt to be flown down from the apparatus in the form of a belt, and curing by cooling during the flowing. A disk roll acts as a pair of tensile rolls and is used to dispose therebetween the belt-like glass melt and forcedly send it downward. In addition to the above-mentioned down-draw method, the plate-shaped glass can be produced by the float method, the roll-out method, the Colburn method, or the like.
In general, a disk roll is obtained by fitting by insertion to a shaft (served as a rotation shaft) a plurality of disk materials obtained by punching a mill board (plate-like molded product, base material) in the form of a ring to obtain a roll-like laminate, and applying a pressure to the entire laminate through a flange provided at both ends. The outer peripheral surface of the disk material functions as the conveying surface of a glass melt.
Since a disk roll conveys a belt-like glass melt, it is not only required to have heat resistance, flexibility and hardness, but also required to prevent the glass surface from getting scratched. Disk rolls containing heat-resistant inorganic fibers, mica and clay are known (Patent Documents 1 to 3).